Orthopedic Materials Research Articles

Silver hydroxyapatite (AgHAP) reinforced nanocomposites of poly (methyl methacrylate)-poly (ɛ-caprolactone) as hybrid orthopedic materials

In the present work, we have reported preparation of silver hydroxyapatite nanoparticles (AgHAPnp) and poly (ɛ-caprolactone)/poly (methyl methacrylate) (PCL/PMMA)/AgHAP nanocomposites using wet chemical precipitation and solvent-casting techniques, respectively. The AgHAPnp and PCL/PMMA/AgHAP nanocomposites were characterized by Fourier transform infrared spectroscopy, X-ray diffraction analysis, field emission-scanning electron microscopy, atomic force microscopy, differential scanning calorimetry, and thermogravimetric analysis techniques. Mechanical properties like microhardness, compressive strength, and modulus of nanocompsoite were also determined. The antibacterial tests were also performed against the species S. aureus and E. coli. In addition, the cytotoxicity of the material was also determined by the MTT assay test.

Enhancement of the mechanical and biological properties on Zn/Ag co-implanted TiN via ions contents regulation

Most orthopedic and dental implants are made of Ti and its alloys due to the excellent biocompatibility and machinability. However, low hardness, biologically inert and poor antibacterial property block its application in the field of hard tissue repair. Therefore, in this study, TiN co-implanted with Zn and Ag (Zn/Ag-TiN) with different contents using the plasma immersion ion implantation system was modified on the surface of titanium alloy to evaluate the mechanical properties, biological properties and antibacterial activities. X-ray photoelectron spectrometer was used to determine the chemical state and composition of samples. The tests of hardness, elastic modulus and scratch of different samples were performed by the nano indenter XP system. Biocompatibility and antibacterial properties were evaluated by MC3T3-E1 cells, bovine serum albumin (BSA) and Escherichia coli (E. coli) in vitro. Results indicate that Zn/Ag(1.5 h)-TiN with the largest content of Zn and Ag exhibits the strongest hardness and adhesion strength, the highest protein adsorption capacity, the best cell adhesion and spreading activity, and ideal proliferation, as well as antibacterial activities, which makes it have great application prospects in orthopedic materials.

In vitro evaluation of poly-ε-caprolactone-hydroxypatite-alumina electrospun fibers on the fibroblast’s proliferation

A biomaterial can replace the function of a real organ, conferring properties of support, regeneration or resistance. In the present investigation, a new composite was developed in the form of a polymeric membrane embedded with hydroxyapatite and alumina particles to be used as scaffolding and to allow cell viability. The support matrix is poly ε-caprolactone, which is a biodegradable polymer, hydroxyapatite is the ceramic that contributes to the improvement of osteoconductive and osteo-regenerative properties, while alumina provides the hardness to the composite for its viable application in the orthopedic industry. The morphology of the composite resulted in an interweaving of fibers with a diameter of 840 ​± ​230 ​nm. The composites were analyzed to the MTT cytotoxicity test, showing that none of the composites were toxic (p ​= ​0.0001); where the PCL/HA/α-Al2O3 composite showed greater cellular viability with 238%, demonstrating its possible usefulness as orthopedic material, in filling fractures, or bone imperfections caused by physical damage.

Dust concentration and awareness of safety and health among orthopaedic clinic staffs in Hospital Kuala Lumpur, Malaysia

Objective: The study was carried out to determine the concentration of total dust from the orthopaedic casting materials exposed to personnel and working area. The determination of knowledge, attitude, and practices (KAP) regarding occupational safety and health (OSH) aspects also conducted. Increase dust concentration above the permissible limit (PEL) would decrease the health status among the staffs. Methods: This cross-sectional study was conducted at the orthopaedic clinic public hospital in Kuala Lumpur, Malaysia. Determination of total dust concentration was using a NIOSH Manual of Analytical Method (NMAM 0501) for 8 hours and a direct reading for 10 minutes. A set of questionnaires assessing the level of KAP related to OSH at the orthopaedic clinic was distributed. Results: The results of total dust concentration in the casting room are 3.402 ± 0.003 mg/m3 from area sampling and for the personal air sampling is 5.573 ± 0.040 mg/m3 which are below than 15 mg/m3 PEL. Percentage of KAP level of OSH in the orthopaedic clinic indicates knowledge (96.75%), attitude (83.7%) and practices (82.85%) respectively. However, this study found that the level of knowledge related to OSH at the orthopaedic clinic had significant relationships (p <0.05) with age, job titles and area of workplaces, while OSH attitudes in orthopaedic clinics had significant relationships (p <0.05) with job titles, use of personal protective equipment (PPE). Level of practice of OSH at orthopaedic clinics, there was significant relationship (p <0.05) with age, job titles and use of PPE. Conclusion: The risk to total dust concentration exposure in this study are relatively low, however, some literature suggested duration of exposure-response even though in the low concentration can be a predisposing factor toward to health occupational illnesses. Medical health surveillance should be implemented in every 6 months to monitor staff’s health status.

Relationships Among Bone Morphological Parameters and Mechanical Properties of Cadaveric Human Vertebral Cancellous Bone.

Mechanical properties and morphological features of the vertebral cancellous bone are related to resistance to fracture and capability of withstanding surgical treatments. In particular, vertebral strength is related to its elastic properties, whereas the ease of fluid motion, related to the success of incorporation orthopedic materials (eg, bone cement), is regulated by the hydraulic permeability (K). It has been shown that both elastic modulus and permeability of a material are affected by its morphology. The objective of this study was to establish relations between local values of K and the aggregate modulus (H), and parameters descriptive of the bone morphology. We hypothesized that multivariate statistical models, by including the contribution of several morphology parameters at once, would provide a strong correlation with K and H of the vertebral cancellous bone. Hence, μCT scans of human lumbar vertebra were used to determine a set of bone morphology descriptors. Subsequently, indentation tests on the bone samples were conducted to determine local values of K and H. Finally, a multivariate approach supported by principal component analysis was adopted to develop predictive statistical models of bone permeability and aggregate modulus as a function of bone morphology descriptors. It was found that linear combinations of bone volume fraction, trabecular thickness, trabecular spacing, structure model index, connectivity density, and degree of anisotropy provide a strong correlation (R 2 ~ 76%) with K and a weaker correlation (R 2 ~ 47%) with H. The results of this study can be exploited in computational mechanics frameworks for investigating the potential mechanical behavior of human vertebra and to develop strategies to treat or prevent pathological conditions such as osteoporosis, age-related bone loss, and vertebral compression fractures. © 2020 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

MiR-21 promotes osseointegration and mineralization through enhancing both osteogenic and osteoclastic expression.

The demand for orthopedic implants continues to increase with the aging population. As the most widely used orthopedic materials, titanium and its alloys have achieved high success rates. However, the lack of bone tissue integration remains a barrier to successful operations. In this study, the titanium surface was acid-treated and functionalized with miR-21 nanocapsules via an in situ polymerization method. This coating showed a uniform miR-21 distribution and sustainable miR-21 release. The in vitro studies indicated that miR-21 could not only promote angiogenic and osteogenic differentiation of MSCs but also enhance osteoclastic activity. Additionally, in vivo evaluations, including X-ray, micro-CT, histology, immunohistochemistry, biomechanical testing, Raman and SEM-EDS, demonstrated that the micro-rough surface could increase the bone-implant contact and, thus, improved osseointegration during the early stages. More importantly, the miR-21 nanocapsule coating accelerated vascularization (high expression of CD31), bone remodeling (high expression of both osteogenesis- and osteoclast-related proteins) and bone maturation (high proportion of apatite), resulting in a significantly improved bone-implant contact and enhanced bone-implant bonding strength (twice the Ti at 1month). These results indicated that a Ti-based micro-rough surface functionalized with miR-21 nanocapsules had potential applications in the orthopedic field.

Biocompatibility, osseointegration, antibacterial and mechanical properties of nanocrystalline Ti-Cu alloy as a new orthopedic material

The demands for high-performance biomaterials are driving the development of new metallic alloys with improved mechanical and biological responses. In this study, a nanocrystalline Ti-Cu intermetallic alloy was prepared by a powder metallurgy route, and its application as an orthopedic material was evaluated by the microstructural, mechanical, corrosion, antibacterial, cytotoxicity and osseointegration examinations. Microstructural characterization revealed the formation of TiCu and Ti2Cu3 as major phases with 23 nm grain size in the structure of the alloy. The synthesized alloy exhibited ultra-high hardness of 10 GPa, acceptable toughness of 8.14 MPam1/2, a ∼98 % anti-bacterial rate against S. aureus and E. coli, excellent cell viability to MG-63 osteosarcoma cells, and high osteoblast formation rate, which indicate a great potential of this alloy for biomedical application.

Poly(l-lactic acid) (PLLA)/MgSO4·7H2O Composite Coating on Magnesium Substrates for Corrosion Protection and Cytocompatibility Promotion.

Magnesium (Mg) and its alloys show excellent potential as orthopedic implantable materials, with their in vivo degraded Mg ions (Mg2+) known to promote the growth of new bone. However, the swift corrosion process during implantation has greatly hindered its clinical applications. A method to counter the high rate of corrosion is to coat Mg substrates on surfaces with a thin layer of biodegradable polymer. Although such a coating reduces the long-term corrosion rate, it also prevents the short-term release of bone-simulating Mg2+ after orthopedic operations. To balance these contradicting short- and long-term characteristics, we present a polymer-inorganic composite coating on pure Mg substrates that enables Mg-based implants to achieve controllable release of Mg2+ and high corrosion resistance simultaneously. The coatings were fabricated by adding an appropriate amount of inorganic magnesium sulfate heptahydrate (MgSO4·7H2O) salt particles into a biodegradable poly(l-lactic acid) (PLLA) polymer matrix, such that they can percolate inside to form an interconnected morphology during the phase separation between Mg salt and PLLA polymers as solvent evaporates during the drying process, resulting in the formation of an organic-inorganic composite coating. The in vitro corrosion tests indicated that the composite coatings with lower Mg salt loading had the best degradation behavior, resulting in controllable release of Mg2+ and alkaline shift. Cytocompatibility of bare and coated Mg were investigated via MC3T3-E1 preosteoblasts through MTT assay and LIVE/DEAD imaging, along with the observation of cell distribution and adhesion behaviors. The results further demonstrated that the incorporation of a suitable amount of Mg salt particles could further improve the cytocompatibility as compared to the pristine PLLA coating. We believe such fabricated organic-inorganic composite coatings could have great potential for application on Mg substrates to obtain Mg-based biomaterials with higher practical value in clinical treatments.

Application of Zr and Ti-Based Bulk Metallic Glasses for Orthopaedic and Dental Device Materials

Conventional orthopaedic and dental device materials are made of metallic materials such as stainless steel (SUS316L), titanium alloy (Ti-6Al-4V), and cobalt-chrome (Co-Cr). Those materials have the disadvantage of mechanical properties and anti-corrosion behavior. Bulk metallic glasses (BMGs), which are also called amorphous alloys, are metallic materials with metastable glassy states and have a higher strength, higher elasticity, higher failure resistance, and lower Young’s modulus compared with crystalline alloys. There are several types of BMGs. Among them, Zr-based BMGs and Ti-based BMGs have excellent mechanical properties. In addition, they have good corrosion resistance and are promising for orthopaedic and dental device materials. In this review article, in vitro and in vivo studies regarding Zr and Ti-based BMGs applications as biomaterials, especially in orthopaedic and dental device materials, are reviewed.

World-Class Tumor Knee Prosthesis: Made in India.

Mega-prostheses required for reconstructing large gaps in bone after limb-saving surgeries for osteo-sarcoma patients have a long development cycle. This includes design of prosthesis components and surgical armamentarium, followed by pilot batch production, lab testing, human clinical trials and regulatory approvals. Most manufacturers stay away due to small market size coupled with the difficulties and high costs involved. Prostheses developed in the West are often unsuitable and unaffordable for the majority of Indian patients. There is a need for high-quality yet low-cost prostheses that are compatible with the anatomy and functionality of local population. An inter-disciplinary group comprising orthopedic oncologists, mechanical engineers and materials scientists from three different organizations in India took up the above challenge. They developed a novel modular tumour knee prosthesis with rotating hinge, as well as surgical armamentarium with femoral and tibial cutting jigs and other instruments. Knee simulator and testing machines were developed to test the prosthesis. A dedicated pilot production facility along with inspection and quality management system was set up. The new prosthesis provides flexion-extension up to 120 degrees and axial rotation of ±5 degrees. It successfully completed ten million cycles of fatigue and wear testing. The regulatory body of the government and institutional ethical committees of hospitals approved the human clinical trials, which are currently in progress. The design, manufacturing and testing of the prosthesis components and armamentarium took more than a decade and presented many challenges. These were overcome by several technological innovations by the engineering team and continuous feedback from the surgeons. The experience is expected to be useful to all others interested in this field.

Covalently functionalized poly(etheretherketone) implants with osteogenic growth peptide (OGP) to improve osteogenesis activity

Polyetheretherketone (PEEK), as the most promising implant material for orthopedics and dental applications, has bone-like stiffness, excellent fatigue resistance, X-ray transparency, and near absence of immune toxicity. However, due to biological inertness, its bone conduction and bone ingrowth performance is limited. The surface modification of PEEK is an option to overcome these shortcomings and retain most of its favorable properties, especially when excellent osseointegration is desired. In this study, a simple reaction procedure was employed to bind the osteogenic growth peptide (OGP) on the surface of PEEK materials by covalent chemical grafting to construct a bioactive interface. The PEEK surface was activated by N,N′-disuccinimidyl carbonate (DSC) after hydroxylation, and then OGP was covalently grafted with amino groups. The functionalized surface of PEEK samples were characterized by X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FT-IR), water contact angle measurement and biological evaluation in vitro. OGP-functionalized PEEK surface significantly promoted the attachment, proliferation, alkaline phosphatase (ALP) activity and mineralization of pre-osteoblast cells (MC3T3-E1). The in vivo rat tibia implantation model is adopted and micro-CT analyses demonstrated that the OGP coating significantly promoted new bone formation around the samples. The in vitro and in vivo results reveal that the modification by covalent chemical functionalization with OGP on PEEK surface can augment new bone formation surrounding implants compared to bare PEEK and PEEK implant modified by covalently attached OGP is promising in orthopedic and dental applications.

Evidence for Gender-Specific Bone Loss Mechanisms in Periprosthetic Osteolysis.

Osteolysis adjacent to total hip replacement (THR) prostheses is a major cause of their eventual failure. Periprosthetic osteolysis is associated with the production of bioactive particles, produced by the wear of articulating prosthesis surfaces. Wear particles invade the periprosthetic tissue, inducing inflammation and bone resorption. Previous studies have shown that osteocytes, the most numerous cell type in mineralised bone, can respond to wear particles of multiple orthopaedic material types. Osteocytes play important roles in bone resorption, regulating bone resorption by osteoclasts and directly through osteocytic osteolysis, also known as perilacunar remodelling. In this study, we perform a histological analysis of bone biopsies obtained from cohorts of male and female patients undergoing either primary THR surgery or revision THR surgery for aseptic loosening. The osteocyte lacunae area (Ot.Lac.Ar) and percentage lacunar area/bone area (%Ot.Lac.Ar/B.Ar) were significantly larger overall in revision THR bone than bone from similar sites in primary THR. Analysis by patient gender showed that increased Ot.Lac.Ar, indicative of increased perilacunar remodelling, was restricted to female revision samples. No significant differences in osteoclast parameters were detectable between the cohorts. These findings suggest previously unrecognised gender-specific mechanisms of bone loss in orthopaedic wear particle-induced osteolysis in humans.

Parametric Effects of Fused Deposition Modelling on the Mechanical Properties of Polylactide Composites: A Review

Polymers are generally inferior in mechanical properties to metals which are the current orthopaedic material for osseointegration in many parts of the world today. This assertion also applies to poly(lactic acid) (PLA), a polyester that has been recently found applicable in tissue remodelling. To improve on its mechanical properties, several processing techniques, inclusive of fused deposition modelling (FDM) also branded as fused filament fabrication (FFF), have been used. FDM has been endeared to many researchers because a range of parameters can be combined to bring about widely different mechanical properties. Although the influence of FDM parameters on the mechanical properties of PLA is clear, the tensile, compressive and flexural strengths obtained so far are inferior to human cortical bone. The need to improve on this production technique for improved mechanical properties is apparent in all the works examined in this review.

Intervención educativa interdisciplinar a grupos de cuidadores

Antecedentes: La calidad de vida de las personas cuidadoras está condicionada por varios factores:el contexto del cuidador, el grado de dependencia del familiar, el tipo de enfermedad, los elementos mediadores (soporte formal de la administración e informal, familiares y amigos). Todo lo anterior demuestra la necesidad de implantar actuaciones encaminadas a apoyar a los cuidadores. Por ello, desde el año 2011, y gracias a la participación de un grupo multidisciplinario de profesionales: enfermería, trabajador social y fisioterapeuta, se decidió elaborar un taller para cuidadores de la zona básica de salud de Carbajales de Alba (Zamora), el 63% de la población son mayores de 75 años con grandes problemas de dependencia. Objetivos: reducir la sobrecarga del cuidador y mejorar su salud. Ofrecerles un programa que combine soporte emocional, educacional y recursos sociales Método: la captación se hace a través de la consulta de enfermería a demanda/programada y trabajador social. Se realiza una vez al año, 3 sesiones de 2 horas de duración. Contenidos formativos: cuidar al que cuida; síndrome del cuidador, alimentación, higiene, prevención de ulceras por presión y caídas, Recursos sociosanitarios, Ley de Dependencia, Catalogo de material orto protésico, ayudas técnicas, aspectos legales, técnicas de movilización y cuidados básicos de la espalda, ejercicios de relajación. Actividades: exposición de los temas anteriormente citados, con apoyo de material audiovisual, y ejercicios prácticos. Participantes: han participado 60 cuidadores, de edades comprendidas entre 46 y 77 años, 50 mujeres y 10 hombres.

Surface Engineering of Biodegradable Magnesium Alloys for Enhanced Orthopedic Implants.

Magnesium (Mg) alloys have been promised for biomedical implants in orthopedic field, however, the fast corrosion rate and mode challenge their clinical application. To push Mg alloys materials into practice, a composite coating with biodegradable and high compatible components to improve anticorrosion property of an Mg alloy (i.e., AZ31) is designed and fabricated. The inner layer is micro-nano structured Mg(OH)2 through hydrothermal treatment. Then stearic acid (SA) is introduced to modify Mg(OH)2 for better reducing the gap below a surface-degradation polymer layer of poly(1,3-trimethylene carbonate). Benefited by the SA modification effect, this sandwiched coating avoids corrosive medium penetration via enhancing the adhesion strength at the interface between outer and inner layers. Both in vitro and in vivo tests indicate that the composite coating modified AZ31 perform a better anticorrosion behavior and biocompatibility compared to bare AZ31. Strikingly, a 1.7-fold improvement in volume of newly formed bone is observed surrounding the composite coating modified implant after 12 week implantation. The sandwiched biocompatible coating strategy paves a hopeful way for future translational application of Mg alloys orthopedic materials in clinics.

Osteoconductive Metallic Implants Using Hydroxyapatite Nanoparticles

Bone is a dynamic and highly vascularized connective tissue that has a unique capability of spontaneous regeneration and to remodel its micro- and macro-structure. The nano-hydroxyapatite has a nano-crystalline feature similar to the bone, thus being used as a bone substitute material. In the case of severe defects, bone would not heal by itself and grafting is required to restore function without damaging living tissues. Most commonly used prostheses material in orthopedics is 316L stainless steel (SS). Due to some problems in SS, various surface modification techniques have been developed to improve the corrosion resistance and biocompatibility of the metals.HA coatings have been extensively studied for the bioactive surface treatment of bio inert metals and ceramics due to its similarity with bone material. This article gives an overview of using hydroxyapatite in preparing osteoconductive metallic implants.

Enzyme responsive titanium substrates with antibacterial property and osteo/angio-genic differentiation potentials

After implantation into a host, titanium (Ti) orthopaedic materials are facing two major clinical challenges: bacterial infection and aseptic loosening, which directly determine the long-term survival of the implant. To endow Ti implant with self-defensive antibacterial properties and desirable osteo/angio-genic differentiation potentials, hyaluronic acid (HA)-gentamicin (Gen) conjugates (HA-Gen) and chitosan (Chi) polyelectrolyte multilayers were constructed on deferoxamine (DFO) loaded titania nanotubes (TNT) substrates via layer-by-layer (LBL) assembly technique, termed as TNT/DFO/HA-Gen. The HA-Gen conjugate was characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (1H NMR). The physicochemical properties of the substrates were characterized by field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and contact angle measurements. The on-demand DFO release was associated with the degradation of multilayers triggered by exogenous hyaluronidase, which indicated enzymatic and bacterial responsiveness. The TNT/DFO/HA-Gen substrates displayed effective antifouling and antibacterial properties against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), while were favourable for the adhesion, proliferation and osteo/angio-genic differentiation of mesenchymal stem cells (MSCs). The multifaceted drug-device combination (DDC) strategy showed potential applications in orthopaedic fields.

Effects of powdered rifampin and vancomycin solutions on biofilm production of staphylococcus aureus on orthopedic implants

PurposeHardware infections in orthopedic surgery, specifically those involving biofilm producing bacteria, are troublesome and are highly resistant to systemic antibiotics. The purpose of this study was to demonstrate the power of rifampin and vancomycin solutions in inhibiting as well as eliminating in vitro on staphylococcus aureus (S. aureus) biofilm in vitro on stainless-steel implants. MethodsA suspension of either S. aureus or a S. aureus containing a plasmid that cods for the green fluorescence protein containing fluorescent protein plasmid was applied to 1 × 1cm sterile stainless steel orthopedic plating material (coupon). Biofilm development was confirmed by; the quantitative assay (colony forming unit [CFU/coupon]) and visualized using confocal laser scanning microscopy. With this established method of biofilm development, we determined the minimum biofilm inhibitory concentration (MBIC) and the minimum biofilm eradication concertation (MBEC) of Rifampicin and Vancomycin. To determine the MBIC, stainless steel plates were subjected to different concentrations of antibiotic solution and inoculated with overnight cultures of S. aureus. After 24 h of incubation at 37 °C, the biofilms on the untreated and antibiotic-treated coupons were quantified. To determine the MBEC, partial S. aureus biofilms were developed on the coupons and then treated with the different concentrations of each antibiotic for 24 h. The number of bacteria within the control untreated as well as treated coupons was determined. ResultsBoth rifampin and vancomycin solutions inhibited biofilm production of S. aureus on stainless steel mediums; the MBIC for rifampin and vancomycin were 80 ng/mL and 1 μg/mL respectively. The MBEC for Rifampicin was similar to the MBIC. However, the MBEC for Vancomycin was 6 mg/ml. ConclusionsWhen applied to orthopedic stainless steel hardware in vitro, solutions of rifampin and vancomycin powder separately or in combination can completely prevent and eliminate biofilm produced by S. aureus. Level of evidenceII

Experimental model of peri-prosthetic infection of the knee caused by Staphylococcus aureus using biomaterials representative of modern TKA.

ABSTRACTProsthetic joint infection (PJI) following total knee arthroplasty (TKA) remains the leading cause for revision surgery, with Staphylococcus aureus the bacterium most frequently responsible. We describe a novel rat model of implant-associated S. aureus infection of the knee using orthopaedic materials relevant to modern TKA. Male Sprague-Dawley rats underwent unilateral knee implant surgery, which involved placement of a cementless, porous titanium implant into the femur, and an ultra-highly cross-linked polyethyelene (UHXLPE) implant into the proximal tibia within a mantle of gentamicin-laden bone cement. S. aureus biofilms were established on the surface of titanium implants prior to implantation into the femur of infected animals, whilst control animals received sterile implants. Compared to controls, the time taken to full weight-bear and recover pre-surgical body weight was greater in the infected group. Neutrophils and C-reactive protein levels were significantly higher in infected compared to control animals at day 5 post surgery, returning to baseline levels for the remainder of the 28-day experimental period. Blood cultures remained negative and additional plasma inflammatory markers were comparable for control and infected animals, consistent with the clinical presentation of delayed-onset PJI. S. aureus was recovered from joint tissue and implants at day 28 post surgery from all animals that received pre-seeded titanium implants, despite the use of antibiotic-laden cement. Persistent localised infection was associated with increased inflammatory responses and radiological changes in peri-implant tissue. The availability of a preclinical model that is reproducible based on the use of current TKA materials and consistent with clinical features of delayed-onset PJI will be valuable for evaluation of innovative therapeutic approaches.

Study of structural, mechanical and dielectrical properties of ions doped apatite for antibacterial activity

Hydroxyapatite doped with disparate ions is synthesized by Sol-gel technique. Hydroxyapatite is a widely bio-ceramic material for orthopedics and dental applications with weak mechanical strength. The hydroxyapatite doped with various ions which is often reported to enhance mechanical strength and to control bacterial infections. The aim of the work concentrates to improve the hardness of the material. Antibacterial activity enhances with the ions which combine with hydroxyapatite. These effects noticeably reveal that the hydroxyapatite can be well utilized with doping ions in order to develop their efficiency against the various bacterial strains. The effect of co-dopants investigated on their phase structure, bond formation, surface and optical properties are studied using X-ray diffraction technique, Fourier Transform Infra-red analysis, Atomic Force Microscopy and Ultraviolet–Visible spectroscopy. The crystalline size of all the synthesized materials varies from 39 to 49 nm. All the composites exhibit hexagonal crystal structure. The functional groups confirm the bonding formation of prepared samples. The surface roughness of hydroxyapatite were successfully analyzed and observed that the dopants increase the roughness. The dielectric property explains the space charge polarization is present at low frequency and negative temperature coefficient of resistance in the prepared samples. The addition of ions improves the mechanical properties of host materials, which well suitable for coating on implantation devices and for various medical applications.